1. Field of the Invention
This invention relates to producing twisted hybrid cords.
2. Description of Related Art
Different types of materials, for example one having a higher modulus and one having a lower modulus, are often used together in hybrid cords for applications such as tire reinforcement. When forming a plied cord, it is common to use different twist levels in the high-modulus ply and the low-modulus ply to account for the difference in modulus between the two materials, or in order to achieve a desired cord response. This currently cannot be achieved on cable corders because they do not form cords in the same manner as ring twisters. Although hybrid cords can be made on cable corders, the cord behavior that can be achieved is limited to that of a balanced twist cord, that is, a cord where the high-modulus and low-modulus ply lengths are the same in which case there is only one response for any given twist level. When an unbalanced hybrid is required, it is currently made on ring twisters. Cable corders provide a tremendous productivity advantage, so it would be desirable to make both balanced and unbalanced hybrids on such machines considering that the unbalanced hybrids are more common than perfectly balanced twist hybrids.